No parent ever wants to know exactly what Mildred Hayes is going through. You can say the canned phrases about sympathies and condolences, but you will never truly know what it feels like to outlive your daughter who was raped, set on fire, and murdered. After seven months of grief, emotional paralysis, and no new information on the perpetrator, Mildred radicalizes. She dons a blue jumpsuit, ties a bandana around her head, and looks ready to take on all comers. To get the town’s attention and give them fair warning she means business and is on the warpath, Mildred advertises on the three billboards near her home on a seldom used back road. Simply, they state her daughter was raped while dying, no arrests have been made, and asks Chief of Police Willoughby why not?

Those are not the most threatening facts and questions ever put on billboards. Drive south on I-95 through the Carolinas and you will see much more in your face messages about abortion, hell, and what the United Nations is doing to you. However, the Ebbing, Missouri Police Department feels threatened by the billboards. How dare a private citizen question the intrepidness of Ebbing’s finest? Mildred (Frances McDormand, Hail, Caeser!) knows full well there will be collateral damage from her provocation, most of all to her son (Lucas Hedges, Lady Bird). But to survive, Mildred must act. From her subjective point of view, which we dutifully follow before meeting Chief Willoughby and his lackluster patrol officer staff, the police nor the town cares too much about justice for young Angela Hayes. They’re about to care.

Writer/director Martin McDonagh, arriving with the crowd-pleasing resumé of In Bruges (2008) and Seven Psychopaths (2012), layers humor on top of the pathos. Mildred grieves and we grieve with her, but we’re all laughing, perhaps to cover up the horror. Many homicides are never wrapped up with a bow with the Clue trifecta of Colonel Mustard in the conservatory with the lead pipe. The cases are nebulous and uncertain. Those who know the victims are angry and in McDonagh’s case, three billboards is their anger. It’s intriguing why and how mere billboards are so confrontational. They’re just words on a large poster. No person speaks them. There is no sound. They’re on a back road with bare minimum drive-by traffic; yet, they are so loud they take over the town.

The man most threatened by these messages is not Chief Willoughby. It is the town’s most inept cop; the one you steer clear of not because he will make sure the guilty party gets theirs, but because he is most likely to accidentally shoot you and himself. Dixon (Sam Rockwell, Laggies) is an angry, violent, and dim-witted mama’s boy. The audience, and Mildred, spends the majority of the film loathing him and his overt racism and ignorance. However, McDonagh’s script handles Dixon with such intense care, and allows him to travel such an amazing arc, you end up sympathizing with him. He is so well written the audience cheered loudly when he marks a certain transition and sticks himself out there to try and do the right thing.

That was not the only time the audience collectively became so overwhelmed with emotion they cheered and shuddered together. McDormand as Mildred became our cause célèbre. Even though Mildred is motivated by righteousness and rage, her actions become increasingly indefensible. We wonder if there is a limit to vengeance and accusations. That is because of Chief Willoughby (Woody Harrelson, The Edge of Seventeen). It is too easy to mock the police for their lack of suspects and arrests; that must mean they are not investigating. However, Harrelson, who in many ways is the heart of the film, reminds us sometimes the killer gets away or cases get solved by the dumbest of luck. Willoughby sees the bigger picture; Mildred sees indifference.

At first, McDormand didn’t even want to play Mildred. She felt too old for the story. Working class folks in rural Missouri do not wait until they are 38 years old to have their first kid. Quite true. But can you imagine anyone else ripping apart reporters, policemen, and drilling holes in the dentist? Filmed in North Carolina with a hint of the nearby Blue Ridge Mountains, Three Billboards doesn’t look too much like Missouri, but it is no distraction. You will be too hooked watching the two-minute long, unbroken scene where Dixon marches across the street, up stairs, commits multiple felonies, and walks back out again. No jump cuts or sly edits.

McDonagh pokes at America’s recent tensions between the police and the citizenry they are charged to protect. Mildred’s refusal to remove the billboards and their increasing omnipresence reminds the department how lowly they are perceived. Mildred reminds them they may have already solved Angela’s murder if they focused more on detective work rather than torturing black people, a charge Dixon hardly denies nor realizes is an insult. Put it all together, and Three Billboards Outside Ebbing, Missouri is a phenomenal cinematic achievement with a perfect script performed by the perfect ensemble. You start out believing you know whose side you’re on; but by the end, you’re questioning whether there are even sides to pick from.